package org.smart4j.framework.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;

/**
 * @author ：Anitaxiaofeng
 * @description：流操作工具类
 * @create 2017-12-15
 **/
public final class StreamUtil {

    private static final Logger LOGGER = LoggerFactory.getLogger(StreamUtil.class);

    /**
     *从输入流中获取字符串
     *  @param is
     * @return
     */
    public static String getString(InputStream is){
        StringBuilder sb = new StringBuilder();
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(is));
            String line;
            while((line = reader.readLine())!=null){
                sb.append(line);
            }
        } catch(Exception e){
            LOGGER.error("get string failure",e);
            throw new RuntimeException(e);
        }
        return sb.toString();
    }

    /**
     * 将输入流复制到输出流
     * @param inputStream
     * @param outputStream
     */
    public static void copyStream(InputStream inputStream, OutputStream outputStream){
        try {
            int length;
            byte[] buffer = new byte[4 * 1024];
            //将inputStream的字节读入到byte中返回的是int就是读到buffer中的字节，如果没有返回为-1
            while ((length = inputStream.read(buffer, 0, buffer.length)) != -1) {
                outputStream.write(buffer,0,length);
            }
            outputStream.flush();
        } catch(Exception e){
            LOGGER.error("copy stream failure",e);
            throw new RuntimeException(e);
        }
        finally {
            try{
                inputStream.close();
                outputStream.close();
            }catch(Exception e){
                LOGGER.error("close stream failure",e);
            }
        }
    }
}
